bioRxiv Science⌕ Search

Biology subjects

Rodberg, E. M.

Publications and source records attributed to Rodberg, E. M..

3 recordsLinked to original sources

Low affinity noradrenergic signaling promotes passive coping during reinforcement behavior

During stress and in many psychiatric disorders the ability to appropriately recognize and respond to cues to avoid negative outcomes (e.g., injury) and achieve positive outcomes (e.g., food) is disrupted. A critical component of the stress response is increased noradrenergic tone, acting on lower affinity noradrenergic receptors (1 and {beta}). Noradrenergic signaling is essential for cue-driven behavior, yet how noradrenergic components of the stress response impacts positive and negative reinforcement behavior is still unknown. We manipulated noradrenergic receptor (1, 2, and {beta}) activity during an active avoidance and reward seeking task in male and female rats. We found modulating noradrenergic activity on low affinity 1 and {beta} receptors but not 2 receptors disrupted reinforcement behavior. Increased 1, but to a greater extent {beta} receptor activity shifted negative reinforcement behavior away from active avoidance and towards passive coping by increasing decision thresholds. We also found sex differences in the impact of 1 and {beta} noradrenergic activity on reward seeking. Overall, stress related noradrenergic signaling deceased active avoidance behavior by shifting strategy towards passive coping. Reward seeking was more robust in females but not males. Collectively these results identify sex differences in noradrenergic dependent stress response behaviors and highlight low affinity adrenoreceptors as relevant therapeutic targets to mitigate the impact of stress on goal-directed behavior. SIGNIFICANCE STATEMENTWhile we know norepinephrine is a fundamental component of the acute stress response, it is unknown how that stress related noradrenergic receptor activity impacts reinforcement behavior, both positive and negative. Here, we show that stress related norepinephrine signaling is differentially involved in positive and negative reinforcement behavior and directly shifts behavioral strategies from active avoidance to passive coping. These results identify that noradrenergic receptor activity can mediate the transition from adaptive to maladaptive behaviors during stress, especially in the context of negative reinforcement.

neuroscience↗

Sex-dependent noradrenergic modulation of premotor cortex during decision making

Rodent premotor cortex (M2) integrates information from sensory and cognitive networks for action selection and planning during goal-directed decision making. M2 function is regulated by cortical inputs and ascending neuromodulators, including norepinephrine (NE) released from the locus coeruleus (LC). LC-NE has been shown to modulate the signal to noise ratio of neural representations in target regions prior to decision execution, to increase the salience of relevant stimuli. Using rats performing a two-alternative forced choice task after administration of a {beta} adrenergic antagonist (propranolol), we show that action planning in M2 is mediated by {beta} adrenergic signaling. Loss of {beta} adrenergic signaling results in failure to suppress irrelevant action plans in M2 that disrupts decoding of cue related information, delays decision times, and increases trial omissions, particularly in females. Furthermore, we identify a potential mechanism for the sex bias in behavioral and neural changes after propranolol administration via differential expression of {beta}2 receptors across sexes, particularly on local inhibitory neurons. Overall, we show a critical role for {beta} adrenergic signaling in M2 during decision making by suppressing irrelevant information to enable efficient action planning and decision execution.

neuroscience↗

Individual differences in behavioral flexibility predict future volitional ethanol consumption in mice

Cognitive control is key to regulating alcohol intake and preventing relapse. Behavioral inflexibility can prevent adaptive strategies such as mindfulness or other relapse-prevention behaviors. In a mouse model we investigated whether individual variability in behavioral flexibility (using attentional set-shifting task; ASST) predicts future alcohol intake. Adult male and female C57BL/6J mice were subjected to ASST using a bowl digging paradigm where mice identify a baited bowl based on compound odor and textural cues. This was completed prior to any alcohol exposure. Individual performance across mice varied within the group. We integrated several metrics, specifically ASST stage completed, trials to completion and errors performed to produce an individual performance index measure of behavioral flexibility. After, ASST mice were trained to drink ethanol (15%, v/v, 1hr/day) for 3-4 weeks until intake stabilized. Using this prospective approach, we identified an inverse relationship between behavioral flexibility and drinking - less flexible mice had a propensity to consume more alcohol. Similar relationships have been identified previously in non-human primates and rats. Our results show that the relationship between alcohol and cognitive flexibility is a robust trait that is conserved across species and can be used in mice to study neural substrates underlying these behaviors. HIGHLIGHTS- ASST can be used to examine individual differences in cognitive function in mice - Behavioral inflexibility is related to future higher alcohol consumption - Executive function can be used as a predictive risk factor for alcohol intake - This relationship in mice supports previous findings across species

neuroscience↗